Leg strength is important yes, but you don't see tennis pro's squatting huge numbers. I would concentrate more on endurance and explosive movements that will help your footwork more than squatting huge amount of weights. Lunges not only help you develop strength, they also mimick some of the movements we do when we get to a ball. Skipping rope is also excellent to develop explosive steps and build your endurance, it will build up your calves as well. If you really insist on squatting or leg press, I suggest you focus on technique and making sure your lower back isn't doing all the work. Lots of lifters tend to increase the lbs which causes they're form to suffer and that usually causes injuries. Building a solid bodyweight squat with perfect form is a good way to start, it will help you build endurance and proper technique before adding weight.
Last edited by Roddick85; 12-23-2012 at 12:49 PM.